> On Tue, Apr 09, 2013 at 05:27:18PM +0000, Christoph Lameter wrote: > > One additional measure that may be useful is to make kswapd prefer one > > specific processor on a socket. Two benefits arise from that: > > > > 1. Better use of cpu caches and therefore higher speed, less > > serialization. > > > > Considering the volume of pages that kswapd can scan when it's active > I would expect that it trashes its cache anyway. The L1 cache would be > flushed after scanning struct pages for just a few MB of memory. > > > 2. Reduction of the disturbances to one processor. > > > > I've never checked it but I would have expected kswapd to stay on the > same processor for significant periods of time. Have you experienced > problems where kswapd bounces around on CPUs within a node causing > workload disruption?
When kswapd shares the same CPU as our main process it causes a measurable drop in response time (graphs show tiny spikes at the same time memory is freed). Would be nice to be able to ensure it runs on a different core than our latency sensitive processes at least. We can pin processes to subsets of cores but I don't think there's a way to keep kswapd from waking up on any of them? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
